Rectifier Tubes Hum?

[Ribboz]

Hey guys :D
I already brought this up on the mesa forums, but I'm getting impatient :D You all have always been so awesome in the past, so I thought I would try here :)

I got a Mesa Roadster recently, love it by the way. There is just one issue. The rectifier tubes hum? At first I assumed it was a normal hum from transformers, but on closer examination the transformers are putting out a lower pitch hum.(almost unnoticeable) It was difficult to break the two apart at first. But it definitely seems that the rectifier tubes are putting out a very high pitch hum/hiss. Its rather annoying, because it seems like I'm the only one who can hear it. Unless I can find a younger person to give it a listen. I just have two questions.

1. Do rectifier tubes normally put out some type of hum?

2. Would replacing the rectifier tubes with solid state replacements remove the sound?

Also any info or advise you can offer would be greatly appreciated :)
Thank you in advance :D

[marauder]

Have you tried switching between spongy and bold?  Bold uses SS rectification.

[Ribboz]

Bold and spongy dont actually have that affect.
Also, even if I'm using the diode tracking instead of recto, there is still a charge going through the recto tubes so the sound still occurs.

Edit: Some current news.

So I was right. It was the recto tubes.
A helpful member on the mesa forum recommended playing it without the recto tubes, and now its dead silent. :D
Just to be safe, I contacted Mesa to make sure it could safely run like this and they said it will work fine. :)

[HTH AMPS]

You can often get the rectifier valve rattling (high pitched) and as you've discovered, its a pain in the arse.  Hence I don't use valve rectifiers.

[Ribboz]

You can often get the rectifier valve rattling (high pitched) and as you've discovered, its a pain in the arse.  Hence I don't use valve rectifiers.

Hmmm.... Do you think tube damping rings might remove the sound?

[HTH AMPS]

You can often get the rectifier valve rattling (high pitched) and as you've discovered, its a pain in the arse.  Hence I don't use valve rectifiers.

Hmmm.... Do you think tube damping rings might remove the sound?

might do, might not - worth a try I suppose.

to be honest, I'd just use a plug-in SS rectifier instead like the Weber Copper Cap.

[Ribboz]

You can often get the rectifier valve rattling (high pitched) and as you've discovered, its a pain in the arse.  Hence I don't use valve rectifiers.

Hmmm.... Do you think tube damping rings might remove the sound?

might do, might not - worth a try I suppose.

to be honest, I'd just use a plug-in SS rectifier instead like the Weber Copper Cap.

Yeah, but that would mean I would have solid state tracking in either setting XD
If I could have recto tubes in, I would. Feels like a waste to not use a somewhat integral part of the amp.
I sorta wish I could have the amp modded, to have 2 el34 tubes put in and take out the recto all together XD Pretty much (Roadster - recto) + progressive linkage from roadking.(or give me the option to mix in 2 el34) Bah I would love that! XD

........is that even remotely possible? *big smile* :D (yeah yeah why didn't I just get the road king XD It just had alot I did not want or need) BUT having the el34s, and no recto, would be considerable :)

[Frank]

Some interesting thoughts on tube rectifiers versus solid state and the possibility of introducing "sag" here ...

http://www.tone-lizard.com/Mods_and_Odds.htm

Scroll nearly to the end for the section on rectification ... though I would add that some of his opinions on amp design and modding may not be to everyone's tastes. Certainly some interesting articles there for the amp tinkerers.

[Dmoney]

the weber copper caps are meant to emulate the recto valves they replace.
I'm thinking of getting a GZ34 replacement to use as a "spare" GZ34 since the amp I built uses a GZ34 and has no other rectifier.

They also do a straight diode replacement. The GZ34 emulator is meant to replicate the sag etc... I'm not sure how true it is.

If that is the case, you'd have switchable diode rectifiers with one setup emulating valve sag. in theory.

My amp that I built uses a GZ34. It doesn't feel saggy at all.

[HTH AMPS]

as Dmoney points out, the Weber Copper Caps do indeed mimic a real recto valve's sag, though the amount of sag in a GZ34/5AR4 is pretty minimal in fairness.  The dual recto uses a 5U4 recto which does have more sag to it, but does anyone really use the valve recto setting? (be honest).  If you MUST have the sag, get the Weber Copper Cap 5U4 replacement and be done with it.

As for output stage valves, the dual rectos have 6L6s right? - not too much of a big deal to change over to EL34s.  I'd need to know the spec of the mains transformer to know whether it can take the extra heater current, but you could always just add a small filament transformer in a worst case scenario.  In short, if you want EL34s in that amp, it can be done.

[Dmoney]

I thought a dual rec was EL34/6L6 switchable?

I've run 5U4 + 6L6
GZ34's with 6V6
and I think GZ34 with EL34.

at least i think I did!

[Ribboz]

First off thanks for all the info guys.

And yeah, its got a switch in the back for switching between el34 and 6l6. I just really liked the idea of the roadkings progressive linkage with the 4 6l6 and 2 el34. Its not a big deal, I was really just throwing it out there for curiosity. If I could have 2 el34 put in and recto taken out completely, it would be a fun idea.

Yeah, I had considered the Copper cap mainly because it seemed like the safest option. But as the stated above, if the sound was merely from rattling(or physical movement of the tubes) then a dampener might fix that. I would rather have the 5u4 instead of solid state simply because I don't want two solid state options :D
Plus I have this weird fascination with tubes XD

Another quick question. Do you guys hear a crackle sound during cool down? not right as its shut down, but as the amp is cooling down.

[Dmoney]

what do you mean?
like after shutdown when the valves are cooling?
or when you have the power on but the amp in standby?
or just after you switch off the power?

I understand now about what you mean about the EL34's. taking out the recto valves and adding 2 extra power valves.
I think that would be really hard in a dual rec. It would be hard in most amps not designed around that initially.

[Ribboz]

what do you mean?
like after shutdown when the valves are cooling?
or when you have the power on but the amp in standby?
or just after you switch off the power?

I understand now about what you mean about the EL34's. taking out the recto valves and adding 2 extra power valves.
I think that would be really hard in a dual rec. It would be hard in most amps not designed around that initially.

Ok I do the normal shut down of a tube amp, go to standby let it sit for a few minutes. Then shut down. For the next five minutes I might hear a crack sound here and there. I cant really describe the sound. "Crackle" is what I'm thinking.

Yeah, I figured as much about the power tubes. It's no biggie :) Thank you for your input through :)

[Dmoney]

crackles on standby... hmmm
I'm not sure if I have heard anything.
When the standby is on, even on low volume, i occasionally hear the odd pop but really rarely.
Sounds normal to me but the others might have some suggestions.

Incidentally. you're not cooling the amp down in that process.
the standby switch cuts the HT voltage to the valves. Pretty much instantly depending on if, or how fast, your filter caps discharge. Even so, when you flick the standby switch the HT usually starts dropping pretty quickly but the valves are not cooling down.

The Heaters are still heating the valves. Hence why they stay illuminated. I believe Leaving a valve heated with no HT on it can actually harm the valves, over a long period of time. I used to do the same as you. But now I let the amp warm up on standby, and when I switch off, I kill the mains rather than let it sit on standby.

you can read about it here. http://www.freewebs.com/valvewizard1/standby.html